1. Field of the Invention
This invention relates generally to transmission line equalization schemes, and more particularly to an equalization scheme based on a Taylor series expansion.
2. Description of the Related Art
A transmission line has an associated frequency response which affects the quality of an input signal propagated on the line. For example, the “skin effect” causes a conductor to have an impedance which increases by the square-root of frequency, which causes an attenuation of the propagated signal at the receiving end of the line.
One method of addressing adverse effects that might arise as a result of a transmission line's frequency response is to receive the propagated signal with a receiver having a frequency response which is the inverse of that of the transmission line, to provide “equalization”—i.e., to restore the magnitude fidelity of the input signal. This approach is described, for example, in A. J. Baker, “An Adaptive Cable Equalizer for Serial Digital Video Rates to 400 Mb/s”, ISSCC 1996 and M. H Shakiba, “A 2.5 Gb/s Adaptive Cable Equalizer”, ISSCC 1999. This approach processes a signal received via a transmission line having a known length with a circuit block having a DC gain of 1, along with multiple frequency-dependent blocks, the outputs of which are summed to provide equalization. Generally, equalization schemes have been implemented digitally; the absolute accuracy of the equalization schemes provided by digital equalizers is often poor, as the accuracy of a digital equalizer is typically considered to be relatively unimportant.